Dual fuel Heat pump and thermostat replacement

Old 04-14-22, 09:40 AM
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
Dual fuel Heat pump and thermostat replacement

My existing system is a Lennox SLP98DFV coupled to a Lennox XP14-042-230 heat pump. These are controlled by a Honeywell Prestige thermostat. The heating/cooling system was not zoned when installed and consequently, with a single thermostat, has hot rooms in the summer and cold rooms in the winter.

We have a portable Honeywell REM5000R1001 thermostat, coupled to the Prestige, that we seasonally move from room to room to meet our comfort needs. I am considering replacing my dual fuel (propane) heat pump with a Lennox ML14XP1-042-230, and the sales representative told me that the existing Honeywell thermostat is not compatible with the new system and that I should install a Lennox S30 thermostat. The Lennox thermostat is not compatible with my portable thermostat and would put us back into the seasonal hot/cold rooms, and offers features that we would never use.

Is the Prestige thermostat really not compatible with the new system or is this simply a sales pitch to add to the total sale?

Last edited by PJmax; 04-14-22 at 10:15 AM. Reason: removed formatting
Old 04-14-22, 10:33 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 70,055
Received 2,953 Votes on 2,664 Posts
Your heat pump is not dual fuel.
A dual fuel system is a heat pump and a gas furnace.
The heat pump is always electric.

Your analog thermostat is not compatible with a communicating system.
It could probably still be used on the furnace as the furnace would be considered strictly backup heat.

I'm not a Lennox representative so I'd need to look up the design specs. of the new heat pump you're looking at but I'd imagine the issue is that it is a communicating system. That means the thermostat sends many commands to the heat pump for maximum performance. It controls variable compressor and variable blower speeds while your current Prestige is on or off only.

Looking at the S30.... it's very expensive and technical. It does a lot. They talk about zoning which would require zoning dampers and sensors. I'm wondering if they could just install remote temp sensors without dampers.
S30 video
The S30 is controllable by an app and that may give you more control over the temperature settings.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: